A word to the wise (was RE: Fw: Scleromochlus)

["Thomas R. Holtz, Jr." <tholtz@geol.umd.edu>]

> From: owner-dinosaur@usc.edu [mailto:owner-dinosaur@usc.edu]On Behalf Of
> Ken Kinman
>
> David and David,
>      Scleromochlus has dorsal body armor???  That does put a
> whole new spin
> on things.
>      But does it have croc-normal ankles?  If not, I can't see it
> as being a
> Suchian.
>      Any possibility it could be a stem-group in a line leading to
> Ornithosuchidae (before developing the diastema and other
> synapomorphies of
> that group)?

Something to keep in mind about Scleromochlus is that the bones are not
preserved in this specimen: the taxon is only preserved in a series of
natural casts (hollow spaces).  Furthermore, it is a little bitty critter
and some of its bones (in the ankle, for instance) would be just about the
same size of the coarse sand grains in which it was preserved.  Therefore,
there is a pretty low amount of fidelity in shape preservation.

Add on top of that there have been several generations of molds taken from
the specimen: each time has the potential to have removed some of the
grains.

In other words, the fossils of Scleromochlus are a bit of a Rorschach test
(as Hans Sues, or Kevin Padian, or SOMEONE once said to me).

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796